This training program is designed to prepare pediatricians for independent, research-oriented careers in academic medicine. Its specific goal is to provide young pediatric investigators with the powerful research tools of molecular and cellular biology that will allow them to explore, in depth, basic questions related to children's health. The 47 program faculty from across the University of Michigan are selected for their demonstrated excellence in training young investigators, the strength of their research programs, and their expertise in one of three areas of pediatric research -- host defenses, developmental biology, and abnormal cellular growth. The trainees supported by this program will be selected from a pool of individuals who have already completed the clinical component of fellowship training (one year) in one of the subspecialty areas of pediatrics. Criteria for choosing these trainees include their potential to be successful investigators, their previous academic records, and their commitment to developing independent, academically-oriented research careers. Each year the program will support five trainees;three to four will be supported in their first year of the research component of their fellowship training, and one to two in the second year. A curriculum is provided for the trainees that takes advantage of the rich educational and research opportunities available at the University of Michigan. Trainees will enroll in the intensive three-month postdoctorate course in Cellular and Molecular Biology offered by the Medical School, will participate in a statistics seminar sponsored by the Department of Pediatrics, in sessions to develop academic skills, in compliance educational modules sponsored by the Medical School, and will present their research at the annual Pediatric Research Day. The focus of the trainee's activities will be an individual research project in the laboratory of the research mentor. In addition, the trainees will participate in research seminars, lectures, and specialized workshops offered by the many basic and clinical sciences units of the University, and will have access to the excellent Medical School core laboratories. As part of their research experience, they will apply for individual awards to support completion of their research training. Progress of the trainees'research work will be monitored by the trainees'research committees;the Program Committee, composed of pediatric faculty;and the Advisory Committee, composed of Medical School faculty outside the Department of Pediatrics. Upon completion of their postdoctoral training, trainees will be board eligible in a pediatric clinical subspeciality, and will be well-prepared for successful careers as independent, research-oriented academic pediatricians.